From 5d8930edfa1d9537ba80e24c0cf8f0c9e4e9ec72 Mon Sep 17 00:00:00 2001
From: Leah Rowe <info@minifree.org>
Date: Wed, 18 Dec 2024 02:06:18 +0000
Subject: [PATCH 32/37] lenovo: Add Kconfig option CONFIG_LENOVO_TBFW_BIN

This is used by lbmk to know where a tb.bin file goes,
when extracting and padding TBT.bin from Lenovo ThunderBolt
firmware updates on T480/T480s and other machines, grabbing
Lenovo update files.

Not used in any builds, so it's not relevant for ./mk inject

However, the ThunderBolt firmware is now auto-downloaded on
T480/T480s. This is not inserted, because it doesn't go in
the main flash, but the resulting ROM image can be flashed
on the TB controller's separate flash chip.

Locations are as follows:

vendorfiles/t480s/tb.bin
vendorfiles/t480/tb.bin

This can be used for other affected ThinkPads when they're
added to Libreboot, but note that Lenovo provides different
TB firmware files for each machine.

Since I assume it's the same TB controller on all of those
machines, I have to wonder: what difference is there between
the various TBT.bin files provided by Lenovo, and how do they
differ in terms of actual flashed configuration?

We simply flash the padded TBT.bin when updating the firmware,
flashing externally. That's what this patch is for, so that
lbmk can auto-download them.

Signed-off-by: Leah Rowe <info@minifree.org>
---
 src/mainboard/lenovo/Kconfig | 26 ++++++++++++++++++++++++++
 1 file changed, 26 insertions(+)

diff --git a/src/mainboard/lenovo/Kconfig b/src/mainboard/lenovo/Kconfig
index 2ffbaab85f..512b326381 100644
--- a/src/mainboard/lenovo/Kconfig
+++ b/src/mainboard/lenovo/Kconfig
@@ -18,4 +18,30 @@ config MAINBOARD_FAMILY
 	string
 	default MAINBOARD_PART_NUMBER
 
+config LENOVO_TBFW_BIN
+	string "Lenovo ThunderBolt firmware bin file"
+	default ""
+	help
+	  ThunderBolt firmware for certain ThinkPad models e.g. T480.
+	  Not used in the actual build. Libreboot's build system uses this
+	  along with config/vendor/*/pkg.cfg entries defining a URL to the
+	  Lenovo download link and hash. The resulting file when processed by
+	  lbmk can be flashed to the ThunderBolt firmware's 25XX NOR device.
+	  Earlier versions of this firmware had debug commands enabled that
+	  sent logs to said flash IC, and it would quickly fill up, bricking
+	  the ThunderBolt controller. With these updates, flashed externally,
+	  you can fix the issue if present or otherwise prevent it. The benefit
+	  here is that you then don't need to use Windows or a boot disk. You
+	  can flash the TB firmware while flashing Libreboot firmware. Easy!
+	  Look for these variables in lbmk:
+	  TBFW_url TBFW_url_bkup TBFW_hash and look at how it handles that and
+	  CONFIG_LENOVO_TBFW_BIN, in lbmk's include/vendor.sh file.
+	  The path set by CONFIG_LENOVO_TBFW_BIN is used by lbmk when extracting
+	  the firmware, putting it at that desired location. In this way, lbmk
+	  can auto-download such firmware. E.g. ./mk -d coreboot t480_fsp_16mb
+	  and it appears at vendorfiles/t480/tb.bin fully padded and everything!
+
+	  Just leave this blank if you don't care about this option. It's not
+	  useful for every ThinkPad, only certain models.
+
 endif # VENDOR_LENOVO
-- 
2.39.5

